(1) Field of the Invention
The present invention relates to a disk storage device, and more particularly to a disk storage device having a modifiable data management function.
(2) Description of the Related Art
Conventionally, a magnetic disk storage device is provided with just simple functional features, such as a function for managing data on a fixed-block-size basis, due to limitations in hardware configuration.
In the SCSI (Small Computer System Interface) scheme which was developed by the ANSI (American National Standard Institute) and has been in widespread use for interfacing between a magnetic disk storage device and a computer, data input/output is carried out in units of blocks (sectors) each having a physically predetermined size, not in data structural units corresponding to logical data aggregates such as files or tables. Since the SCSI is applicable just to a relatively low level of interfacing, it is required to provide a file system or a database management system to be carried out on a host computer (or disk server) directly connected with the conventional magnetic disk storage device in the case of implementation of high-level interfacing capable of transferring logical data blocks such as files or tables, for example. Further, since the conventional magnetic disk storage device is not provided with an interface mechanism for direct connection to a communication network, intervention of the host computer directly connected with the magnetic disk storage device is required for an application program running on another computer to input data to a remote magnetic disk storage device or to output data therefrom.
In the background of rapid advances in hardware technologies and trends toward lower cost of hardware, an NASD (Network-Attached Secure Disk) has recently been proposed by G. Gibson of Carnegie-Mellon University (Proceedings of the 8th ASPLOS Conference, 1998), which is a magnetic disk storage device having a communication network connection interface mechanism that enables direct input/output of magnetic disk data through a remote computer without intervention of a host computer. In addition to the network connection interface mechanism, the NASD is also provided with a function for managing stored data so as to enable accessing each logical aggregate structure of data such as a file, for example.
Examined hereinbelow is the technique of OLAP (Online Analytical Processing) for data mining and decision-making system applications that are expected to proliferate in the near future. In OLAP for market trend forecasting, for example, business data querying processing is carried out frequently to find out any data meeting a certain condition among a large amount of data. In a conventional data query system, all the business data under search examination are read out sequentially from magnetic disk storage, and a computer makes a judgment whether or not each data meets a specified search condition to find out desired data. Therefore, most data not meeting the specified search condition are transferred to the computer uselessly in consequence. In this situation, if only the data meeting the specified search condition can be transferred to the computer by feeding the specified search condition to the magnetic disk storage, the amount of data transferred from the magnetic disk storage to the computer is decreased significantly to enable substantial reduction in work load on the computer.
It is possible to speed up data analysis and image processing by providing magnetic disk storage with functions for supporting OLAP and image processing, which has been suggested in evaluation experiments conducted at Carnegie-Mellon University (Proceedings of the 24th VLDB Conference, 1998) and University of Californiaxe2x80x94Santa Barbara (Proceedings of the 8th ASPLOS Conference, 1998).
The above-noted NASD has been proposed since it has become costwise feasible to incorporate a hardware function for processing data in units of logical data into magnetic disk storage thanks to rapid advances in hardware technologies accompanied with substantial reduction in cost of hardware. As expected at present, further progress in hardware technologies will still reduce hardware cost, making it possible to provide magnetic disk storage with more advanced functions.
However, merely fixed functionality is provided in the NASD. For example, in the NASD, it is not allowed to discretionarily add any function (object management function) for managing stored data in access units of logical data structures such as directories or folders (hereinafter referred to as objects) or to arbitrarily modify an object management function in part. Further, while the performance of the conventional magnetic disk storage device can be improved substantially using a data caching function, the NASD does not allow a user to modify any data management attribute concerning the data caching function, for example, or to add such an extended function as an OLAP support function.
It is therefore an object of the present invention to provide a disk storage device having a modifiable object management function.
Another object of the present invention is to provide a disk storage device which allows a user to specify and modify file organization, object management attributes, and extended functionality.
In accomplishing these objects of the present invention and according to one aspect thereof, there is provided a disk storage device comprising: a disk storage medium; a network interface; a disk controller having an object management function in which a high-level read/write command specified for an access target using an object identifier received through the network interface is converted into a low-level read/write command containing physical address information of the disk storage medium for making access to the disk storage medium; and object management modification means for modifying the object management function in response to a modification request message received through the network interface.
According to another aspect of the present invention, there is provided a disk storage device comprising: a disk storage medium, a disk controller for accessing the disk storage medium to read/write data thereon; an interface for connecting the disk storage device to a network; object management means for converting a control command containing an object identifier received through the interface into a control command containing physical address information of the disk storage medium and for feeding the thus converted control command to the disk controller; and object management modification means for modifying a function of the object management means in response to a modification request message received through the interface.
More particularly, according to the present invention, the modification request message contains at least one of parameters concerning file organization, data management attributes and data processing in correspondence with each partition identifier, and the object management modification means modifies at least one of functions concerning file organization, data management attributes and data processing, which are provided in the object management means, according to the parameter contained in the modification request message.